Hi MamaTanya, I don't know your play style but I strongly recommend ignoring defenses until around level 40. You will be attacked about the same no matter what. I prefer a strong offense that allows me to raid most bases on my map and get resources I need when it's time to upgrade.
Here's my personal order of preference in development:
1. HQ. (Key to everything in Boom Beach!)
2. Radar (allows you to get more bases on your map for more resources and to find new heros.)
3. Armory (allows you to upgrade troops so you can become more powerful, helping in raiding more bases on your map for more resources!)
4. Landing Craft (Allows your boats to carry more troops to attack with.)
NOTE: Landing Craft are "hard" to upgrade because basically they're out of use until upgrade is complete, leaving you with fewer troops to raid with. Also, 3 and 4 are sort of interchangeable. You want to plan to upgrade your armory after a troop is finished upgrading AND a landing craft is finished upgrading.
5. Vault (whether you go offense or defense you will be attacked. Upgrading vault reduces losses.)
6. Gunboat (for more GBE!)
7. Storage units for all resources.
I think that's about it. You can ignore upgrading defenses until about level 39 when you'll be forced to (only thing left to upgrade to get HQ up another level).
Best advice: Do not use Green statues or blue statues. It's tempting but greens are really useless unless you NEVER get attacked, but first time you get attacked, all the benefits of the green statues are lost. Your attacker thanks you for building extra resources for him.
Focus on Purple (GBE, PSC, Resource Rewards) initially. Also reds for Troop Damage and Troop Health.
I personally hate tanks but probably 90% of the people who play boom beach love them and boom beach tends to cater to them (tanks+medics are vastly overpowered and require little to no skill). Tanks were the last unit I upgraded to max. I'm a zooka player and love the high damage zookas do, but Supercell has it out for us LOL (so it seems).
Good luck to you and your husband!